Afternoon all. I recently modded a secondhand canon 600D by removing the LPF2 and leaving in the LPF1 filter. I think it is working well with fortunately little sensor tilt as far as I can tell. I recently posted a photo of the Stature of Liberty nebula in the beginner's section. My next step was to get a light pollution filter. My setup is a skywatcher quattro F4 250mm newtonian with the skywatcher quattro F4 coma corrector, which attaches to the canon with T adapter. I live in the northern light-polluted suburbs of Brisbane.
I need advice with which filter to get and where to put it in the optical train.
The retained LPF1 filter is an IR cut off filter. Is this adequate or should I get a filter which also has IR cutoff in it. Some possiblities are CLS ( no IR filter), CLS-CCD ( has IR filter) , L enhance, L extreme. I could get a clip in filter or a normal filter which ? might be able go into the T adapter? There seems to be little leeway to put it elsewhere as the sensor to coma corrector distance is 55mm. Is astronomik or optolong the way to go. Any experience or advice welcome.
Cheers,Rob.
you can screw 2" threaded filters to the front end of your coma corrector without worrying about back focus. just screw it on and go.
as for filters we have so many different banded filters to choose from that i really dont no witch ones are best. i do not like the broadband filters iv found a uv/ir cut filter produces a better image on galaxys and dimmer/darker targets i will get gradients being bortal 7 and mabe the moons out but i can fix it up in pixinsight.
my antlia ho/sii filter produces halo's on bright stars and my antlia ha/oiii doesnt. iv had an l extreme and it was extreme halo's. askar, altair also produce one-shot colour narrowband filters but i have no experience with them
For OSC and DSLR cameras in a Newtonian Reflector at focal ratio f4 to f6 , the 2” ALPT dualband filter ( 5nm Ha 5nm Oiii ) or 2” Optolong L Ultimate dualband filter ( 3nm Ha 3nm Oiii ) will do a suburb job under heavy light pollution when imaging emission nebula ( useless for galaxies , globs and reflection nebula , screws up your colour ) Star halos shouldn’t be an issue.
Just screw the filter on the end of your coma corrector. It will change focus a bit but not f ratio.
I used the Antlia ALPT with my 2600MC in 6” , 8” and 10” Newts for a few years and it was significantly better than the L Extreme, which caused obvious halos. I started with screwing the filter on the end of my TS GOU coma corrector but then changed to a ZWO filter drawer for OSC cameras.
Thanks, Jordo and Martin for the advice. Those filters look great. With a modded DSLR, is it better to screw the filter into the end of the corrector or use a camera clip in.
Has anyone tried the Antlia RGB Triband Ultra filter.
Cheers, Rob
